Copeland Ultratech 2 Stage Compressor - Opinions

BigRob

Hey all, I've been trying to learn more about the latest and greatest technology in our industry. I've read about the different modulating compressor technologies:

2-stage
Digital
Variable speed

From what I saw on youtube the copeland digital units don't seem to save much: unloaded 3.8A, loaded 5.8A.

The variable speed stuff is pretty neat, but the drive electronics seem like a reliability issue, at least in the short term. Plus, the cost of all the electronics.

I like the 2-stage variable capacity compressors - simple modulation control, and you aren't wasting any energy like the digital compressors.

Seems to me if they made an ultratech 3 stage, we could modulate, for example, at 33%, 66%, and 100%, then PWM between the stages with pretty basic controls and no complex motor drives.

SWEI

The complex motor drives are getting less expensive and more reliable every few years. Pair that with a permanent magnet motor and you get both a jump in efficiency and much higher turndown.

Dave0176

Yes frequency drives are turning up on everything these days.

BigRob

Do you guys know of any good whitepapers or resources regarding compressor control strategies? I'm curious how the variable speed units are controlled.

aircooled81

Regarding staging, most txv's can handle down to 50% capacity. When you get into 33% capacity due to compressor unloading, you may need to load a smaller txv. That would be where you had multiple stage txv's and coils. Obviously not practical with a single evap single txv residential set-up.
I have started-up the danfoss variable speed compressors driven off a drive on intellipaks. They cover them with a metal box and padding because they are loud. They also seem to vibrate a bit at the highest speeds. They work great!
I haven't seen this applied to residential yet. I have seen the dc driven compressors on ductless splits and multi zone condensers. Those are fairly quiet in my opinion.

This article doesnt speak to design, but does explain 4 styles of compressor staging:
http://www.emersonclimate.com/Documents/Products/Compressors/modulation-technologies/offline/download.pdf

Regarding design, I think these are going to have a rough start in the beggining when they hit the mass residential market. When unoading down to 50%, you can really start lowering gas velocities. I'll bet this is going to give these units a bad wrap, as linesets are not going to be properly sized to deal with things like oil return in some applications.

njtommy

When using two stage compressors first stage is 70% of the btus. The second stage is the 30%. It's not that much of a difference, but I'm assuming it could make a difference in the homes performance with longer run times.

The inverter stuff or VRF they use EXV that are capable of 350-400steps aka stepper motor. They EXV has a ton of load capacity adjustments.

unclejohn

Three years ago I installed a Carrier 19 SEER two stage heat pump and removed a Carrier 15 SEER single stage heat pump. My power bill went up about 1/3. The unit never shuts off. Gimme a single speed hi SEER unit any day. I can live with two degree temp fluctuations.

BigRob

unclejohn said:

Three years ago I installed a Carrier 19 SEER two stage heat pump and removed a Carrier 15 SEER single stage heat pump. My power bill went up about 1/3. The unit never shuts off. Gimme a single speed hi SEER unit any day. I can live with two degree temp fluctuations.

I've been wondering about that, for example, is there guidance on proper control of run time and indoor temperature vs. energy use?

unclejohn, do you know if your condenser fan and evaporator fan are multi-speed? Maybe you can tweak you thermostat to run on high?

BigRob

aircooled81 said:

Regarding staging, most txv's can handle down to 50% capacity. When you get into 33% capacity due to compressor unloading, you may need to load a smaller txv. That would be where you had multiple stage txv's and coils. Obviously not practical with a single evap single txv residential set-up.
I have started-up the danfoss variable speed compressors driven off a drive on intellipaks. They cover them with a metal box and padding because they are loud. They also seem to vibrate a bit at the highest speeds. They work great!
I haven't seen this applied to residential yet. I have seen the dc driven compressors on ductless splits and multi zone condensers. Those are fairly quiet in my opinion.

This article doesnt speak to design, but does explain 4 styles of compressor staging:
http://www.emersonclimate.com/Documents/Products/Compressors/modulation-technologies/offline/download.pdf

Regarding design, I think these are going to have a rough start in the beggining when they hit the mass residential market. When unoading down to 50%, you can really start lowering gas velocities. I'll bet this is going to give these units a bad wrap, as linesets are not going to be properly sized to deal with things like oil return in some applications.

I was reading about that the other day and it made me wonder about my condo. The condenser is on the 9th story roof and I'm on level three. I've never been happy with the performance - need to look at the compressor and line length limits and pop on some gauges.

Have you ever used these? I can't tell if they're available in the US - the Danfoss websites are so bad.

http://variablespeed.danfoss.com/Products/Inverter-scroll-VRJ.htm

http://www.ra.danfoss.com/TechnicalInfo/Literature/Manuals/17/FRCC.EK.019.A2.22.pdf

It looks like a solid setup. Let me know if you know where to source the parts.

BigRob

njtommy said:

When using two stage compressors first stage is 70% of the btus. The second stage is the 30%. It's not that much of a difference, but I'm assuming it could make a difference in the homes performance with longer run times.



The inverter stuff or VRF they use EXV that are capable of 350-400steps aka stepper motor. They EXV has a ton of load capacity adjustments.

EXV's are the way to go. Pretty cool. Did you see this link posted above?

http://www.emersonclimate.com/Documents/Products/Compressors/modulation-technologies/offline/download.pdf

Interesting info.

aircooled81 said:

Regarding staging, most txv's can handle down to 50% capacity. When you get into 33% capacity due to compressor unloading, you may need to load a smaller txv. That would be where you had multiple stage txv's and coils. Obviously not practical with a single evap single txv residential set-up.
I have started-up the danfoss variable speed compressors driven off a drive on intellipaks. They cover them with a metal box and padding because they are loud. They also seem to vibrate a bit at the highest speeds. They work great!
I haven't seen this applied to residential yet. I have seen the dc driven compressors on ductless splits and multi zone condensers. Those are fairly quiet in my opinion.

This article doesnt speak to design, but does explain 4 styles of compressor staging:
http://www.emersonclimate.com/Documents/Products/Compressors/modulation-technologies/offline/download.pdf

Regarding design, I think these are going to have a rough start in the beggining when they hit the mass residential market. When unoading down to 50%, you can really start lowering gas velocities. I'll bet this is going to give these units a bad wrap, as linesets are not going to be properly sized to deal with things like oil return in some applications.

Great link! Pretty interesting Emerson admits their digital stuff is not very efficient at part loads, which makes sense. I'm surprised they don't integrate a fully variable mechanical capacity control.

njtommy

I clicked the link have yet to have time to read it but here is an EXV from a York screw chiller.

njtommy

@unclejohn I'm not really surprised that your bill went up a bit hopefully it made the house more comfortable. How do you have your system staged? Also are you zoning duct work off of it as well?

I've been think of going 2 stage or variable speed. I have a few years hopefully to still decide my heat pump and Ahu are only 8 years old.

unclejohn

No zoning. I think I can latch in below a certain temp so the compressor will run only on high stage. Haven't done that yet.

njtommy

Keep us posted on that uncle John.

SWEI

Very little experience here with the two stage Copeland, but I can say that properly sized and commissioned inverter (VFD) stuff works fabulously (and consumes quite a bit less power.)

BigRob

SWEI said:

Very little experience here with the two stage Copeland, but I can say that properly sized and commissioned inverter (VFD) stuff works fabulously (and consumes quite a bit less power.)

Wish there were some inverter retrofit kits out on the market.

njtommy

@BigRob they do.

http://www.emersonclimate.com/en-us/services/aftermarket/pages/scroll-digital-upgrade-kit.aspx

BigRob

njtommy said:

@BigRob they do.



http://www.emersonclimate.com/en-us/services/aftermarket/pages/scroll-digital-upgrade-kit.aspx

Hey NJ, I saw that. I'm not a fan of the digital scrolls, though. I do like these:

http://variablespeed.danfoss.com/Products/Inverter-scroll-VRJ.htm

http://www.ra.danfoss.com/TechnicalInfo/Literature/Manuals/17/FRCC.EK.019.A2.22.pdf

Probably non available in the US?

njtommy

I really don't see too many Danfoss comps. Really only in Carrier aquasnap chillers.

BigRob

SWEI said:

Very little experience here with the two stage Copeland, but I can say that properly sized and commissioned inverter (VFD) stuff works fabulously (and consumes quite a bit less power.)

I wonder how the performance would be if some of the controls from a variable speed compressor were installed on a 2 stage compressor? For example, variable speed condenser fans for subcooling control. I'm still learning this stuff. If anybody knows any good modern HVAC compressor control resources, they would be appreciated.

njtommy

@bigrob check out the ICM fan speed controls. They are like little VFDs for the condenser fans. You can use them on both sleeve and ball bearing motors.

SWEI

Permanent magnet synchronous motors (aka DC inverter compressors) are the future. Look what they have done to the small circulator market already.

They will be a true game-changer when they hit commercial refrigeration.

BigRob

SWEI said:

Permanent magnet synchronous motors (aka DC inverter compressors) are the future. Look what they have done to the small circulator market already.

They will be a true game-changer when they hit commercial refrigeration.

I believe it. Recently, I've been trying to understand which "levers" have the biggest impact. I found this doc last night and it was eye opening.

http://www.emersonclimate.com/en-us/WhitePapers/Optimum-Refrigeration-Control-with-E2.pdf

I'm still a little hazy on how the suction pressure regulator interacts with the rest of the system- gotta keep reading.

My goal is to find the most simple bang for the buck control system.

SWEI

BigRob said:

I found this doc last night and it was eye opening.

http://www.emersonclimate.com/en-us/WhitePapers/Optimum-Refrigeration-Control-with-E2.pdf

Excellent read. Lots of moving parts, but when you get them all playing well together, the results can really be impressive.

The performance we are seeing from current mini-splits (the good ones) are edging up on theoretical limits. Refrigeration is overdue for a shake-up.

SWEI

http://www.carelusa.com/heos-sistema won the 2016 AHRI Innovation Award for refrigeration. More hydronics!

BigRob

SWEI said:

http://www.carelusa.com/heos-sistema won the 2016 AHRI Innovation Award for refrigeration. More hydronics!

So I guess the condenser plant keeps the condenser side conditions consistent and optimal for the motor and exv's? Plus less volume and copper used indoors. Pretty cool.

njtommy

Inverters and water source condensers. Not a bad idea for supermarkets.

SWEI

Basically packaged systems at the units (with nice, short refrigerant circuits) and then water/glycol to the outdoors.

I've been looking at a simpler version of this to handle a couple of walk-ins and an ice machine. Here in the US, water-cooled condenser options are somewhat limited, which I was somewhat mystified by. Turns out that historically these have been cooled by fresh, potable water that goes down the drain. The water bills were not pretty.

My plan was to pipe the cooling water through a reverse indirect and use that for preheating DHW. The Carel units would give much better temp control in the box and use a fair bit less electricity. I like.

njtommy

yes pump and dump aka water wasters are and have been around for years. I've worked on plenty of water cooled condensers systems for refrigeration, chillers and Heat pumps. The Eagles stadium has all water source condensers for the refrigeration. It's way better to have water source over air source condensers. It saves a lot of maintenance on cleaning condensers in every kitchen. I will also guarantee it saves on compressor failures too from not having dirty coils and very high space temps.